Similarities between the Forssman carotid syndrome and experimental allergic encephalomyelitis

Induction of anti-Forssman antibodies in the hamster-to-rat xenotransplantation model

BACKGROUND

In the hamster-to-rat heart xenotransplantation model, the serum response of the host contributes to determine whether the xenograft is accommodated or rejected.

METHODS

To further characterize the serum response in this model, we compared anti-hamster antibodies found in naive LEW-1A rats, or in LEW-1A rats rejecting or accommodating a hamster heart, using a combination of cobra venom factor (CVF) and cyclosporin A (CsA) given for 10 days, and then CsA alone.

RESULTS

Hamster hearts grafted into rat recipients contained IgG and IgA deposits to the same extent whether the xenograft was rejected or accommodated. Only immunoglobulins of the IgM isotype were found to be more abundant in recipients rejecting their graft. A significant part of this IgM response was directed toward the Forssman antigen, a sphingolipid present in the hamster but not in the rat. However, although anti-Forssman antibodies bind in situ to hamster tissues, this binding was not able to induce hyperacute rejection after antibody transfer. Furthermore, depletion of anti-Forssman antibodies from a rejecting serum did not modify its rejection properties.

CONCLUSION

Unlike the pig-to-primate discordant xenotransplantation model, in which preexisting anti-carbohydrate antibodies are directly responsible for hyperacute rejection, in the concordant hamster-to-rat situation, the evoked IgM anti-Forssman carbohydrate antibodies do not appear to be the main cause of the vascular rejection.

Anticardiolipin antibodies in patients with rabies vaccination induced neurological complications and other neurological diseases

We reported the occurrence of anticardiolipin antibodies (ACA) by using an enzyme-linked immunosorbent assay (ELISA) in sera of patients with neurologic complications from Semple rabies vaccination. There was a correlation between the presence of ACA and the disease severity. Sixteen of 25 patients (64%) with major neurological complications, 2 of 21 patients (10%) with minor complications, and non of the normal vaccinees had an ACA response. In comparison to this, ACA was found in 10/43 (24%) of patients with post-infectious encephalitis (PIE), Guillain-Barré syndrome (GBS) and multiple sclerosis (MS), 5/22 (23%) and 4/31 (13%) of patients with degenerative neurological diseases and central nervous system (CNS) infections, respectively. There was no specific restriction to any particular isotype. Frequency difference of ACA responses was unremarkable in systemic lupus erythematosus (SLE) patients with (3/9) and without (3/10) CNS involvement. It is not conclusive about the pathogenetic role of ACA. This remains to be determined.

Autoantibodies to brain endothelial cells in the sera of patients with human T-lymphotropic virus type I associated myelopathy and other demyelinating disorders

We examined the sera of 21 cases of human T-lymphotropic virus type I (HTLV-1)-associated myelopathy (HAM), 30 cases of neuro-Behçet (N-B) syndrome, and 36 cases of multiple sclerosis (MS) for the presence of autoantibodies to brain endothelial cells by enzyme-linked immunosorbent assay (ELISA) using cultured brain endothelial cells. The concentrations of immunoglobulin G (IgG) which bound to brain endothelial cells were significantly increased in the sera of patients with HAM before (P less than 0.001) and after (P less than 0.01) blocking Fc receptors compared to those of controls. The levels of IgG binding to brain endothelial cells were also significantly increased in the sera of patients with N-B syndrome (P less than 0.01), and MS (P less than 0.001) especially those in an exacerbation compared to those of controls regardless of blocking Fc receptors. These results suggest that IgG binding to brain endothelial cells may be mediated via an immunologically specific antigen-antibody interaction as a result of the blood-brain barrier (BBB) damage in cases of HAM, N-B syndrome and MS.

Autoimmune encephalomyelitis in rhesus monkeys induced by immunization with cerebral endothelial cell membrane

It is postulated that multiple sclerosis might be an autoimmune demyelinating disease of the central nervous system (CNS). The mechanisms involved are unknown but, since the blood-brain barrier (BBB) is damaged, injury to endothelial cells is likely to have occurred. Our previous studies have led us to investigate the autoimmune effect of injuring the blood-brain barrier by immunizing rhesus monkeys with an endothelial cell membrane from the same kind of animals. The immunized animals developed a chronic or a relapsing neurological illness. Histological and ultrastructural examinations of the brain in the acute stage showed infiltrates of mononuclear cells around the blood vessels of the white matter of cerebrum, cerebellum, pons and midbrain, while in the chronic phase, large areas of demyelination and remyelination, especially in the white matter regions, were present. The animals immunized with extraneural antigen, an endothelial cell membrane obtained from human umbilical cord, developed no neurological illness. This results indicate that the brain endothelial cell membrane has an inflammatory encephalitogenic activity which could produce widespread demyelination in animals. The animal model described here may prove to be useful in the pathogenetic investigation of human autoimmune demyelinating diseases.

Anti-endothelial cell antibodies and circulating immune complexes in the sera of patients with multiple sclerosis

Sera from patients with multiple sclerosis (MS) were examined for anti-endothelial cell antibodies and immune complexes by enzyme-linked immunosorbent assays (ELISAs) using cultured brain endothelial cells and Raji cells respectively. The concentrations of immunoglobulin (Ig) G which bound to cerebral endothelial cells and of immune complexes were significantly increased in the sera of patients with MS, especially those with an exacerbation. The levels of IgG binding to endothelial cells were still increased in the sera of exacerbated MS patients after blocking Fc receptors compared to those of controls. These findings indicate that IgG binding to endothelial cells may be mediated via an immunologically specific antigen-antibody interaction. The results show that anti-endothelial cell antibodies and immune complexes are present in cases of MS and they may play a pathogenetic role in the blood-brain barrier (BBB) damage.

A new model for multiple sclerosis: chronic experimental allergic encephalomyelitis induced by immunization with cerebral endothelial cell membrane

Multiple sclerosis is considered to be an autoimmune demyelinating disease of the central nervous system. Damage to the blood-brain barrier, of which endothelial cells are the main constituent, occurs in multiple sclerosis, probably due to immunological mechanisms. We report here the results of immune-mediated damage to these cells, produced by immunizing guinea pigs with an endothelial cell membrane fraction. The fraction was obtained from cerebral endothelial cells grown in vitro and was free from myelin basic protein. The immunized animals developed a chronic neurological illness with evidence of delayed hypersensitivity to the cell membrane fraction but not to myelin antigens. Histological examination of the brain in the acute stage showed mononuclear cell infiltrates around blood vessels, while in the chronic phase large areas of demyelination, especially in the periventricular region, were present. This bore a striking similarity to the brain in multiple sclerosis. This may prove to be a useful new animal model for the investigation of the human demyelinating disease.